3 22X XY X+ = +2 6 61X Y X XY− + = + + + =XY X Y1 7+ + =...
Bài 1.
3
2
2
x xy x+ = +2 6 61x y x xy− + = + + + =xy x y1 7+ + =2
2
4x y x y3
2
2
x xy x+ = +2 6 61x y x xy− + = + + + =xy x y1 7+ + =2
2
4x y x y